     ;; (send! {:tag :runtimes :runtimes runtimes})
 
     (if (empty? runtimes)
-      (send! {:tag :err :msg "No available JS runtimes!"})
+      (send! {:tag :err :val "No available JS runtimes!"})
       ;; work loop
       (let [session-id (str (UUID/randomUUID))
             session-ns 'cljs.user

               (let [{:keys [error? ex source]} msg]
                 (cond
                   error?
                   (do (send! {:tag :err :msg (str "Failed to read: " ex)})
                       (recur loop-state))

                   (= ":repl/quit" source)

  (start-server svc :browser {:port 12345})
  (stop-server-for-build svc :browser)
  (stop svc)
  )
